In a small bowl, mix the dry brine ingredients together. Place your turkey breast on a rimmed baking sheet or in a large baking dish. Gently pull the skin away from the meat to create a little space between the skin and meat. Sprinkle the dry brine liberally all over the turkey breast, including under the skin and on the underside. Gently rub the brine into the meat until it's well coated. Transfer the turkey to the fridge uncovered for 24 hours.

Preheat an oven to 350 degrees F. Remove the turkey from the fridge and allow to come to room temperature for 30 minutes.

In a large roasting pan, toss together the potatoes, shallots, garlic, bacon, oil, salt, and pepper until well-combined. Evenly spread the sprigs of rosemary and fresh thyme over the potatoes. Place the turkey breast on top of the potatoes, and smear the skin with the softened butter all over.

Insert a probe thermometer into the thickest part of the breast. Leaving the display portion of the thermometer on the kitchen counter (or near the oven), place the roasting pan in the oven. Roast for about an hour and 45 minutes. After an hour, remove the roasting pan from the oven, toss the potatoes, and then return the roasting pan to the oven. Once the internal temperature of the turkey reaches 150 degrees F, increase the temperature to 375 degrees F for about 15 minutes, until the internal temperature reaches 160 degrees F.

Remove the roasting pan from the oven and gently tent the turkey breast with foil. Allow the turkey to rest for 20 minutes before slicing. Serve warm.